A. Field of the Invention
The present invention relates to a medical treatment device utilizing an ultrasonic wave and, more particularly, to a medical treatment device used, for example, for resecting a human tissue of interest or breaking a stone in a body cavity by ultrasonic vibrations.
B. Description of the Prior Art
Conventional resection treatment of a human tissue of interest is to cauterize the tissue of interest with an RF current to resect the tissue.
According to this treatment, however, the cauterized tissue is degenerated into whitish tissue, and thus it is difficult to judge the resection area. Therefore, the conventional treatment poses a problem wherein even normal tissue tends to be resected.
In order to solve the problem posed by the conventional treatment, another resection treatment with ultrasonic vibrations has been recently practiced by a treatment device using such vibrations. A conventional treatment device using ultrasonic vibrations is proposed in Japanese Patent Application No. 60-1201 (Japanese Patent Disclosure, Kokai, No. 61-159953). This treatment device comprises a probe, that is, a vibration transmission member which is made of a pipe or the like and can be inserted in a living organism, and an ultrasonic vibrator, that is, an ultrasonic vibration generating means connected to the proximal end of the probe through a horn. In order to resect the tissue of interest, the distal end of the probe is inserted in a body cavity through, e.g., an endoscope channel inserted in the body cavity, and the distal end is urged against the tissue. The distal end of the probe is then vibrated to resect the tissue of interest. This treatment can also be applied to break a stone in a body cavity.
In a treatment using the above ultrasonic treatment device, an operator can erroneously damage blood vessels, thereby causing bleeding. When bleeding occurs, the probe inserted in the body cavity is removed, and a hemostatic instrument is inserted in the body cavity.
According to this conventional treatment, every time bleeding occurs, the instrument must be replaced, and the replacement operation is burdensome.
As disclosed in Japanese Patent Disclosure No. 52-93 (USP No. 3,990,452, DE 2626 373 132), a probe having a bent portion at its distal end is mounted on a treatment device utilizing ultrasonic vibrations. This device is used in a treatment. Vibrations having a predetermined amplitude are transmitted from an ultrasonic vibration generating means to the distal end of the probe, and the vibration frequency is controlled such that the distal end of the probe serves as a portion having a largest vibration magnitude, that is, a loop of the vibration. The treatment device is used as a device for resection of, e.g., tissue to be cured, by utilizing ultrasonic vibrations at the distal end of the probe.
A device with a probe having a bent portion at its distal end can be conveniently used in a limited body cavity and can be easily operated. However, the distal end of the probe is vibrating in only one direction, and thus reduces the capacity for resecting the tissue in a living organism or breaking a stone therein. Therefore, a strong demand has arisen for a treatment device utilizing ultrasonic vibrations having a high resection or breaking capacity.